The present invention relates to a robot control device and a robot system.
Typically, an industrial robot system includes an industrial robot and a robot control device connected to the industrial robot through a power supply cable and a signal cable. As described in JP-A-11-188686 and JP-A-9-198120, the industrial robot receives a signal from the robot control device and operates in accordance with the signal.
To save space in a production facility, it is now desirable to reduce the size of the robot control device. However, since various heat sources including a servo amplifier are stored in a casing of the robot control device, the heat radiating surface area of the casing as a whole must be relatively great so as to cool the heat sources. Alternatively, a large-sized fan may be provided to forcibly cool the interior of the casing. The size of the casing of the robot control device thus becomes large, which makes miniaturization of the robot control device difficult. Further, the above-described two publications do not teach a cooling structure that operates in correspondence with the amount of the heat generated by the heat sources.
JP-A-6-216552 has proposed a technique that improves cooling efficiency of such electronic devices. Specifically, electronic element mounting surfaces of print circuit boards, each of which is arranged in the vicinity of a side surface of a casing, are oriented in such a manner as to face inward with respect to the casing. This orientation exposes the electronic elements in the vicinity of the side surfaces of the casing to the cooling air flowing at an increased flow rate. This enhances the cooling efficiency of the print circuit boards. Alternatively, as described in JP-A-2002-353679, a cooling duct having a vent hole is provided in the casing. A plurality of heat lanes extend from the cooling duct. A servo amplifier, a power supply, and a transformer are connected to the corresponding ones of the heat lanes. This arrangement permits transportation of a large amount of heat through the heat lanes, improving cooling efficiency of the heat generating bodies.
Nonetheless, in the technique of JP-A-6-216552, improvement of the cooling efficiency is not achieved in the entire portion of the interior of the casing but restricted to the vicinity of the side surfaces of the casing. In JP-A-2002-353679, the cooling duct, which is provided independently, enlarges the size of the casing, making it impossible to reduce the size of the robot control device.